As a compressor for a vehicle air conditioning system, a double-headed piston type compressor as disclosed in, for example, Patent Document 1 has been proposed. The cylinder block of this type of compressor includes cylinder bores for accommodating double-headed pistons. A swash plate, which operates together with a rotary shaft, causes the double-headed pistons to reciprocate in the cylinder bores. The double-headed piston type compressor includes compression chambers defined in each cylinder bore on both ends of the associated double-headed piston. Each double-headed piston compresses refrigerant drawn into the associated compression chambers, and discharges the compressed refrigerant to the outside of the compression chambers. Patent Document 1 discloses a compressor in which rotary valves are employed as a mechanism for drawing in refrigerant into the compression chambers, and a compressor in which suction valves are employed as a mechanism for drawing refrigerant into the compression chambers.
In these days, engines are made quieter to reduce noise in compartments of vehicles (in particular, automobiles). Thus, there is a demand for quieter compressors used in vehicle air conditioning systems. However, in the conventional compressor disclosed in Patent Document 1, noise and vibration are generated due to pulsation (pressure fluctuation) caused in the compressor. These noise and vibration are transmitted from the compressor to the passenger compartment through conduits, thereby generating noise in the passenger compartment. Thus, in the conventional compressor, sufficient measures are hardly taken to reduce noise to a desired level.
[Patent Document 1] Japanese Laid-Open Patent Publication No. 5-312146